A differential device, also known as a differential gear, is commonly used on the transmission mechanism of automobile tires. Since the distance traveled by the left and rights tires when the automobile is making a turn is different, the number of revolution cycles is different too. Herein, a differential device is employed to rotate the left and rights tires in opposite directions, as known as the effect of “differential”. Generally, current differential devices achieve countermovement of the two output shafts by gearing drive of bevel gear. However, as the gearing drive between the bevel gear, the input shaft and two output shafts is single side direction, the drive force and its stability of this kind of bevel gear drive structure is far from desirable. Furthermore, as far as a bevel gear is concerned, the augmentation of its size is less likely to bring about effective increases of such variables as modulus and number of teeth, which are critical for the increase of its friction. Consequently, this kind of differential device has little room for any improvement. Therefore, an ideal and practical new differential device offsetting such shortcomings is called for in relevant industry.
In light of this and drawing on years' experiences in the manufacturing and designing work of relevant products, this inventor proposes a practical design after careful evaluation and design to achieve such purposes.